“The unicorn of Divvy bikes,” as city Transportation Commissioner Gabe Klein called it, is currently on the street among the otherwise blue rides available for rent at stations set up mainly from the near South Side through downtown to the North Side.

People who see it this month and take photos or shoot video of the red bike can enter to win gift certificates from local companies by posting pictures online with the hash tag #divvyred, Klein said. Annual Divvy memberships will be given out to the 25th, 50th, 75th, 100th, 200th and 300th people who rent the red bike this month.

The distinctive paint job is meant to match the red stars on the city flag, a contrast to the blue-painted Divvy bicycles modeled on the Chicago flag's stripes, Klein said during a news conference at Fosco Park in the University Village neighborhood.

When it was suggested that the red evoked the St. Louis Cardinals, the mayor balked at riding it, perhaps considering the optics of being linked to the arch-enemies of a considerable portion of the Chicago electorate. “You ruined it. You made it impossible,” said Emanuel, who relented and took a short spin around the park before locking the red bike into the Divvy station near the field house.

Klein said that with 117 rental stations set up as of Thursday, Chicago’s system is now the fourth largest in the U.S. By next spring, the city plans to have 400 stations with 4,000 bikes, which Emanuel said will make it the largest in the country.

A Tribune analysis last month showed Chicago’s bike-sharing network, centered around CTA stations and the city’s most densely-populated neighborhoods, is far more convenient in areas with large white populations than in spots where lots of African-Americans, Hispanics or other minorities live.